Plasticizers are compounds or mixtures of compounds that are added to polymer resins to impart softness and flexibility. Phthalic acid diesters (also known as “phthalates”) are known plasticizers in many flexible polymer products, such as polymer products formed from polyvinyl chloride (PVC) and other vinyl polymers.
Phthalate plasticizers have recently come under intense scrutiny by public interest groups that are concerned about the negative environmental impact of phthalates and potential adverse health effects in humans (especially children) exposed to phthalates.
Epoxidized vegetable oils (such as epoxidized soybean oil, ESO) are known to be effective substitutes for phthalic acid diesters as coplasticizers and costabilizers for vinyl chloride resins, such as polyvinyl chloride (PVC). Epoxidized vegetable oil plasticizers are conventionally used in only small proportions (typically no more than 5 to 15 wt %) in a polymer matrix because the presence of a larger amount (greater than 15 wt %) tends to result in exudation (“spew”). Epoxidized vegetable oils also have the tendency to degrade at elevated temperatures. Such degradation is problematic as it causes the polymer to become brittle and discolored upon heat aging.
A need exists for epoxidized fatty acid ester that does not exude when applied as a plasticizer to polymeric compositions. A further need exists for polymeric compositions with epoxidized fatty acid ester plasticizer that are spew-free and are also thermally stable.